JP3275045B2 - Preparation of thermoplastic aromatic polyester - Google Patents

Abstract

Thermoplastic aromatic polyesters possessing high resistance to degradation in the molten state, are obtained by a two-stage polycondensation process comprising: a) reacting an aromatic dicarboxylic acid, or a derivative thereof esterified with a volatile alcohol, with an excess of a diol, until the dicarboxylic acid diglycolester or a mixture of oligomers thereof is formed; b) polycondensing the dicarboxylic acid diglycolester to obtain the thermoplastic aromatic polyester; wherein in stage b) or preferably in both stages a) and b) of the process a salt or a saline complex, soluble in the reacting mixture, of a metal chosen from the group comprising lanthanides (or rare earths) having an atomic number equal to or greater than 62 is used as catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a thermoplastic polyester having a high degree of stability in a molten state and a method for producing the same.

Specifically, the present invention is based on thermoplastic polyesters containing units derived from aromatic dicarboxylic acids which are alternated with units derived from diols, and the formation of ester groups by condensation or transesterification reactions. Related to the manufacturing method.

[0003] Thermoplastic aromatic polyesters, more specifically polyethylene terephthalate (PET), are widely used polymers with very good mechanical properties,
Generally used in the production of fibers, sheets, plates or molded articles (eg containers, parts, etc.).

[0004] These end products are generally produced by a process of processing molten polyester (eg, extrusion, blow molding, heat molding, etc.), and all of these processes bring the polymer to high temperatures, usually above 200 ° C. Leave for at least a few minutes (more than 10-20 minutes in certain cases). In addition, it may be necessary to process the polyester several times in the molten state to obtain the final product.

[0005] Due to high temperatures under conditions of considerable mechanical stress, especially as occurs during extrusion or injection molding,
Polyesters are subject to degradation, leading to lower average molecular weight, uncontrollable reduction in linearity, and decolorization and embrittlement of the polymer after coagulation.

Preparation of polyesters (20 during bulk polymerization)
(Temperature maintained above 0 ° C.).

[0007] Numerous investigations have been made to overcome the disadvantages of thermal degradation of PET and other thermoplastic polyesters, and various solutions have been proposed in the literature.

[0008] In particular, it has been recognized that acid or base impurities derived from the catalyst used in its manufacture serve to promote thermal degradation of the polyester.

A widely recognized (eg, GC Eastmon)
d et al. Comprehensive Polymer Science, Pergamon Pres
s, Oxford, 1989, Vol. 5, p. As disclosed in U.S. Pat. Nos. 275 to 315, thermoplastic polyesters are produced by various methods, all of which involve a condensation reaction accompanied by formation of an ester group. In particular, aromatic polyesters are usually prepared by reacting a diol with a derivative esterified with an aromatic dicarboxylic acid or a volatile alcohol (eg, methanol or ethanol).

[0010] The manufacturing method is performed in two stages, and in the first stage,
The diacid or its esterified derivative is reacted with an excess of the diol to remove water or alcohol formed during the reaction. In the second stage, which is carried out under reduced pressure at a temperature above 200 ° C., the excess diol is removed with the formation of the polyester. The catalyst used in both the first and second stages is preferably of the acid type, and can perform its catalytic function in a single stage or in both stages, depending on the type. Catalysts particularly used for the industrial production of polyesters include, for example, acetates of sulfuric acid, lead, calcium, zinc or manganese,
Oxides of titanium alkoxide, germanium and antimony, especially the latter for the second polymerization stage. Further details on both other processes for the preparation of thermoplastic aromatic polyesters and other catalysts used can be found in the above-mentioned document Com.
shown in prehensive Polymer Science. However, according to the inventors' experience, these catalysts have sufficient thermal stability of the polymers to allow their use in more complex processes or in the production of very high quality products. Is not guaranteed.

The preparation of thermoplastic polyesters using special lanthanum, cerium or neodymium compounds as catalysts is also disclosed in the literature.

In particular, US Pat. No. 3,489,722 discloses polyethylene terephthalate (PE) having reduced yellowing
The process of T) is disclosed wherein a Ce or La salt (acetate, nitrate or chloride) in combination with an organic phosphite or phosphate is used.

US Pat. No. 3,118,861 reports the use of neodymium oxide as a catalyst in the production of high purity PET. However, in this process, the catalyst system has insufficient activity and cannot achieve high production levels for the same molar amount (as currently required in the global polyester market).

As a result, despite the large literature existing in the art, the known methods of making PET or other thermoplastic aromatic polyesters are entirely satisfactory for many techniques relating to the use of such polymers. Not something. This is especially important in processes where PET is used as a mixture with other polymers.

In this sense, the situation that arises when such polyesters are mixed with polymers containing groups that can chemically react with ester groups (eg amides or carbonates) is particularly complicated. In these cases, the uncontrolled progress of these interactions leads to a gradual loss of the advantageous synergistic properties of the mixture.

The inventors have found that when the aromatic polyester obtained by the method of the present invention is used, the above-mentioned disadvantages can be totally solved. Specifically, these polyesters have high average molecular weights and are processed by conventional conversion methods without undergoing degradation or yellowing,
It shows excellent stability even in a mixture with another polymer obtained by a polycondensation reaction.

As described above, the present invention provides a method for producing a high-temperature-stable thermoplastic polyester by polycondensation in the presence of a special catalyst capable of reducing the degree of deterioration of a molten polyester.

Specifically, the present invention relates to a process comprising the steps of: a) removing an esterified derivative of an aromatic dicarboxylic acid or a volatile alcohol with an excess of diol by simultaneously removing water or volatile alcohol formed during the reaction. While substantially reacting until a mixture of dicarboxylic acid diglycol esters or oligomers thereof is obtained; b) releasing the mixture of dicarboxylic acid diglycol esters or oligomers thereof obtained in the step a) during the polycondensation. The polycondensation until a thermoplastic aromatic polyester is obtained, while simultaneously removing the excess glycol to be obtained. In step b) or preferably in both steps a) and b), an atomic number of 62 or more is used. Using a salt or salt complex soluble in a reaction mixture of a metal selected from the group consisting of lanthanoids (or rare earths) DOO provides the preparation of thermoplastic aromatic polyesters, wherein.

More specifically, the metal is samarium,
It is selected from europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium, preferably from samarium, europium, gadolinium, terbium, dysprosium, holmium and erbium. Salts or salt complexes of samarium and europium are particularly suitable for the purposes of the present invention.

The process of the present invention can produce polyesters having surprisingly high thermal and chemical stability starting from known dicarboxylic acids and diols commonly used for the production of polyesters.

The aromatic dicarboxylic acids used in step a) of the present invention are generally of the general formula (I) HOOC-Ar-COOH, where Ar is a C _6-20 divalent aromatic residue, For example, o-, p- or m-phenylene, methylphenylene, chlorophenylene, dimethylphenylene, phenylenedimethylene, diphenylene, methanediphenylene, 2,2-propanediphenylene, diphenylene ether, diphenylene sulfone, naphthalene, anthracene and the like Is a compound represented by:

Ar may be a divalent heteroaromatic residue (eg pyridine, thiophene, furan and the corresponding alkyl or halogen substituted nucleus).

Preferred dicarboxylic acids for the purposes of the present invention are phthalic acid and naphthalenedicarboxylic acid. Particularly, terephthalic acid is preferred.

As used herein, the term "aromatic dicarboxylic acid" refers to a mixture of two or more dicarboxylic acids represented by the general formula (I) and 20 mol% or less, preferably 10 mol% or less with the dicarboxylic acid. And mixtures thereof with an aliphatic dicarboxylic acid (eg, succinic acid or adipic acid). Furthermore, the term "aromatic dicarboxylic acid" refers to the compound and up to 20 mol%, preferably up to 10 mol%, of hydroxyaromatic derivatives such as m- and p-hydroxybenzoic acid, hydroxynaphthoic acid and 2-hydroxyethylbenzoic acid. Acid).

In the method of the present invention, a derivative in which one or both carboxyl groups of the dicarboxylic acid are esterified with a volatile alcohol can also be used. The diester obtained by esterifying the carboxylic acid with an alcohol which is volatile or in any case easily removed by evaporation during step a) of the process of the invention is useful for producing the polyesters of the invention. Particularly useful. Representative aromatic dicarboxylic acid derivatives suitable for use in the present invention are the C _1-5 aliphatic alcohol diesters of acids of general formula (I), such as dimethyl, diethyl and dibutyl esters.

For the present invention, it is preferred to carry out step a) starting from diesters rather than using free acids. In particular, dimethyl ester (specifically, dimethyl terephthalate) is preferable.

Suitable diols for the preparation of the polyesters of the present invention include all the usual compounds containing two hydroxyl groups per molecule commonly used for the preparation of polyesters of the prior art. These compounds are also commonly known as glycols and make it possible to obtain linear polyesters.

Diols which can be used in connection with the present invention include, for example, aliphatic glycols of the general formula HO- (CH ₂ ) _n OH, where n is an integer from 1 to 10. Representative diols include diethylene glycol, triethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, 1,4-
There are cyclohexanediol and 1,4-dimethylolcyclohexane.

The term "diol" used in the present invention
Also encompasses mixtures of glycols with small amounts (generally up to 10% by weight, based on glycol) of triols or polyols having a higher functionality, if branched thermoplastic polyesters are desired.

The scope of the present invention includes both linear and branched thermoplastic polyesters obtained by the process of the present invention.

Finally, diols or polyols obtained by the oligomerization or polymerization reaction of glycols (for example diethylene glycol or propylene glycol) or olefinic oxides (for example ethylene oxide or propylene oxide) are also preferably combined with one or more of the above-mentioned diols. Used in the present invention. These diols or polyols are generally structural formula (II) - (O-CH 2 -CHR-) m - ( wherein, R represents hydrogen or a methyl group; m is 2-50
0, preferably an integer from 2 to 300).

Suitable salts or salt complexes of samarium or europium used as catalyst in the process according to the invention are present in the reaction mixture of step b) and preferably of step a) in an amount sufficient to at least catalyze the reaction. It is a soluble inorganic or preferably organic salt.

The inorganic salt suitable for the present invention is represented by the following general formula (III): MX _p L _{q wherein} M is a metal selected from the group of lanthanoids having an atomic number of 62 to 71, preferably Sm or Eu; Is a monovalent inorganic counter ion (eg, chlorine, bromine or fluorine ion,
Each of the q L's independently represents a neutral ligand; p represents the oxidation state of the metal M, (p + q) being at most 8, And preferably 2 or 3 under the condition of an integer of 2 to 6).

Other compounds used as catalysts in the process of the present invention include compounds of the general formula (IV) MY _p L _{q wherein} each of the p Ys independently represents a monodentate organic anion; L, p and q are those of the above general formula (III) under the condition that (p + q) is an integer of at most 8, preferably 2 to 6.
Is the same as that in the above).

Y is an anion derived from an aliphatic, alicyclic or aromatic carboxylic acid, or sulfonic acid, sulfinic acid,
An anion derived from phosphonic acid or phosphinic acid, or an alkoxide, allyloxide or carbamate anion.

Y may be an anion of a dicarboxylic acid (eg isophthalic acid, oxalic acid or malonic acid) or, if p = 3, a combination of a dicarboxylate and a monofunctional anion.

Representative examples of Y from carboxylic or dicarboxylic acids included within the scope of the present invention include formate, acetate, chloroacetate, propionate, butyrate, hexanoate, decanoate, palmitate, stearate, cyclohexyl. Sanoate, benzoate, chlorobenzoate, hydroxybenzoate, toluate, ethylbenzoate, octylbenzoate, 4-phenylbenzoate, naphthoate, 2
-There are furancarboxylates, isophthalates, malonates, adipates and similar anions. Other examples of anions included within the meaning of Y include phenate,
2,6-dimethylphenate, methoxide, ethoxide,
There are propoxide, isopropoxide, butoxide, ethyl carbamate, phenyl carbamate, benzenesulfonate, benzenephosphonate ion and the like.

Suitable for the purposes of the present invention are benzoate, acetate, propionate, phenate, 2,6-
Dimethylphenate, propoxide, isopropoxide and butoxide ions.

The neutral ligand which is the ligand (L) of samarium or europium in the catalyst of the present invention includes all those generally known to those familiar with the organometallic chemistry of such metals. . Non-ionic molecules containing at least one heteroatom (eg, N, P, O or S) in addition to H ₂ O and NH ₃ (which are the most common inorganic neutral ligands) (N containing at least one electron doublet used for coordination is preferred). These ligands act as ligands for metal M with the base Lewis center located on the heteroatom.

For the purposes of the present invention, one of the above metals M
Substantially all of the known different types of organic neutral ligands which can form suitable complexes can be used. Many of these ligands are described in Gmelin Handbuck der Anorganischen C
hemie, Coordination Compounds of Sc, Y, La to Lu,
Vol. D1-D4, 8th edition, Springer Verlag, Berlin (1980-
1986), and reference is also made to this invention.

A preferred ligand for preparing the catalyst of the present invention is characterized by two or more heteroatoms selected from N, P, O and S, and a position coordinated with the same metal atom M. And a bidentate or polydentate ligand. Representative examples of these ligands (do not limit the invention)
Is a β-diketone or β-ketoester (eg, acetylacetone or methylacetylacetonate), o-
Dipyridyl, 8-hydroxy-quinoline or crown esters (eg compounds known as benzo-12-crown-4 and benzo-16-crown-5).

In the case of a complex having at least one polydentate ligand, q in the general formulas (III) and (IV) indicates the number of ligands, and is smaller than the number of coordinating atoms.

Other compounds suitable for the purposes of the present invention are complexes of the above lanthanoids (M) with one or more bidentate or polydentate anionic ligands. Among these, the general formula (V) in B _i ML _j (wherein, M and L is as defined above; B is a bidentate anionic ligand, and i represents the oxidation state of the metal, provided that (2i + j) is an integer of 4 to 8, preferably 6 to 8.).

The bidentate anion ligand B of the present invention comprises a metal M
And generally 5 to 7 atoms (including metal M) in the ring
Is an organic anion that can form a cyclic structure having

Representative examples of, but not limited to, bidentate anion ligands used to form complexes of general formula (V) are salicylates and acyl salicylates (eg, acetyl salicylates). Rate), β-diketonate (for example, acetylacetonate), orthoformylphenolate, 2-pyridylcarboxylate, aminoacetate, 3-aminopropionate, 2-aminophenolate and the like.

The inventors have surprisingly found that complexes containing a bidentate anion ligand of the general formula (V) not only exhibit high catalytic activity, but are also particularly large if other conditions are the same. It has been found that a polyester having a molecular weight can be produced.

A process for preparing a thermoplastic polyester characterized by the use of a catalyst containing a bidentate anion ligand of the general formula (V) is particularly suitable for the purposes of the present invention.

Finally, the present invention provides, within its spirit,
Catalysts comprising binuclear or polynuclear compounds of the above-mentioned lanthanoids (belonging to the above-mentioned classes) (the above-mentioned general formulas (III), (IV)
And (V) are not strictly included).

Representative examples of the salts and complexes suitable for the present invention include Eu (acetylacetonate) ₃ dipyridyl, Sm (acetylacetonate) ₃ dipyridyl, Sm (2-formylphenate) ₃ , samarium triacetate 6 It is a hydrate.

The compounds represented by the above general formulas (III), (IV) and (V) can be prepared by a general method which constitutes a part of the inorganic and organometallic chemistry of lanthanoids (in this regard, there are many literatures) Respectively).
Many of these general methods, along with a number of specific examples, are described above in Gmelin Handbuck der Anorganischen Chemi.
e, Coordination Compounds of Sc, Y, and La to Lu. Other preparation methods, such as Nouveau
Traite de Chemie Mineral, Vol. VII, Masson & C. P
ublisher, France (1959).

One of the above formulas (III), (IV) and (V)
One of the salts or complexes included in step b) of the process of the present invention
Only (especially when using non-esterified dicarboxylic acids which do not require a specific catalyst for step a)) or as catalyst in both steps a) and b). In the latter case, their use is particularly convenient and is preferred when using an esterified derivative of a dicarboxylic acid in step a).

Based on the experiments performed by the inventors, it was surprisingly found that lanthanoids between samarium and lutetium of the general formula (IV) or (V), in particular organic salts of samarium or europium, were used. In this case, it has been found that the catalyst activity is particularly high.

The catalyst for the process according to the invention is generally used in an amount of from 0.01 to 2% by weight, based on the dicarboxylic acid. Preferably it is added to the reaction mixture in an amount of 0.05-0.5% by weight. At these concentrations, the catalyst exhibits catalytic activity comparable to or higher than that of known catalysts.

The process of the present invention is carried out under the conditions generally used for producing known thermoplastic aromatic polyesters. These conditions will vary depending on the monomers initially used and the size and type of equipment used and the degree of polymerization desired, but are not critical for the purposes of the present invention.

In general, step a) comprises slowly stirring
The reaction is carried out at a temperature of 150 to 220 ° C. while gradually distilling off the water and alcohol formed during the reaction. Step b) is generally carried out at a temperature of 190-300 ° C., preferably 240-280 ° C., at a pressure of 10-300 ° C.
Performed at 1000 huskals.

In a typical process carried out in accordance with the present invention, a dimethyl ester of an aromatic dicarboxylic acid (eg, dimethyl terephthalate or dimethyl isophthalate or a mixture thereof) is added in excess molar amount (2/1) of a diol (eg, ethylene glycol or (Tetramethylene glycol). In order to improve the impact strength of the final polyester, a suitable amount (5 to
20% by weight) of polyethylene glycol or other high molecular weight glycol can be added to the mixture.

Then, a suitable amount of a catalyst in the form of a soluble Sm or Eu complex (generally 0.1 to 0.3% by weight based on dimethyl ester) is added to the monomer mixture. The temperature of the mixture is then raised to about 180-200 ° C. and the methanol formed during the reaction between the diol and the carboxylic acid dimethyl ester is distilled off.

When no more methanol is generated, the temperature is further increased to 220-230 ° C. and the pressure is gradually reduced to about 30-50 Pascals. The excess glycol generated during the transesterification starts to distill off. Then
Gradually increase the temperature to a maximum of about 280-290 ° C, and further reduce the pressure to 10-20 Pascals. During the distillation of excess glycol, the reaction mixture increases in molecular weight and viscosity,
When all of the excess glycol has been removed, a molten polyester is obtained. Then, the molten polyester is drawn or extruded to obtain fibers or granules.

The thermoplastic aromatic polyester obtained by the method of the present invention has a high resistance to deterioration in the molten state and has the general formula (VI)-(-OD-OCO-A-CO -)-(Wherein, D and A are a divalent organic residue derived from a diol and an organic residue derived from an aromatic dicarboxylic acid, respectively). is there.
These polyesters also generally contain trace amounts of metals belonging to the above-mentioned lanthanoids derived from the catalyst used in their production according to the invention, the metals not being separated and remaining dispersed in the polyester mass. I do.

These are crystalline thermoplastic polymers such as PET or polybutylene terephthalate, or amorphous thermoplastic polymers such as PET or copolyesters containing terephthalic and isophthalic acid units. These polyesters generally have a molecular weight of 5,000 to 100,000, preferably 15,000 to 50,000.

In particular, the PET obtained by the method of the present invention has an intrinsic viscosity (measured in a 40/60 (w / w) phenol / tetrachloroethane solution) of at least 0.3 dl / g, generally 0.5 dl / g.
1 dl / g. The intrinsic viscosity of the preferred PET is 0.6-0.9
dl / g.

The process of the present invention is not limited to the production of aromatic polyesters containing only units derived from aromatic dicarboxylic acids and diols, but rather the units plus other small amounts co-condensable therewith (generally from 0 to 0). The same advantage is used in obtaining a copolymer containing units of (15 mol%). These units are derived, for example, from diamines (hexamethylenediamine, diphenylenediamine or polyoxyethylenediamine) or hydroxyamines (hydroxyethylamine), in which case the process according to the invention gives copolyesteramides.

Other co-condensable units include hydroxycarboxylic acids or aminocarboxylic acids (preferably aromatic; for example 4-hydroxybenzoic acid and 4-aminobenzoic acid) and the corresponding methyl esters.

The present invention also includes a copolymer obtained by preparing a low-molecular-weight polyester (oligoester) by the method of the present invention and then reacting it with an aliphatic or aromatic diisocyanate or polyisocyanate. It is. These products are linear or branched thermoplastic polyesters containing small amounts of urethane groups.

[0065] The thermoplastic polyesters of the present invention can contain other additives, such as nucleants, stabilizers, flame retardants, flow agents, antioxidants, pigments, inorganic fillers and fiber reinforcing agents. These additives are well known to those familiar with the operation of replacing polyester with the final product and act to impart special properties to the polymer required for optimal use of the final product. For example, nucleants suitable for PET are many sodium carboxylate salts, and stabilizers and antioxidants include highly sterically hindered hydroquinones and phenols. Inorganic fillers for increasing the rigidity of the thermoplastic polymer are usually inert salts such as mica, kaolin, calcium sulfate, titanium oxide, talc, glass beads, aluminum sulfate, whiskers and the like.

The fiber reinforcing agents used in the polyesters of the present invention, especially polyethylene terephthalate, include commercially available glass fibers having various sizes, rock wool, metal fibers and carbon fibers.

A special class of additives for the polyesters of the present invention are polymeric tougheners. These are polymers having a glass transition temperature of 0 ° C. or lower, and are linear block elastomers or polyolefins, or graft or crosslinked copolymers.

These are preferably added to the polyester by mixing in the melt in an extruder to form a phase dispersed within the polyester.

Examples of such a polymer toughener include polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile, ethylene-propylene rubber, polyisobutene, polypropylene, polyethylene, ethylene-propylene-non-conjugated diene terpolymer (EPDM). , Polybutyl acrylate and other elastomeric acrylic copolymers, ethylene-acrylic acid copolymers and the like.
Another example of a toughener suitable for the polyesters of the present invention is a linear matrix formed from one of the above-described polymers or copolymers, on which a polar or polarizable unsaturated compound (eg, a saturated Acrylic or methacrylic esters of aliphatic alcohols, vinyl acetate, acrylonitrile,
(A block obtained by polymerization of styrene and substituted styrene) is grafted).

Such a polymer additive is added to the polyester of the present invention in an amount of 30% by weight or less, preferably 10 to 25% by weight based on the polyester.

The thermoplastic aromatic polyester of the present invention comprises
It has excellent chemical, thermal, mechanical and rheological properties combined. In particular, besides retaining the excellent mechanical properties of the known polyesters, they are susceptible to thermal degradation, which is one of the most significant disadvantages when dealing with polymers in the molten state and when recycling scrap. It shows moderate resistance. Due to the reduced polyester deterioration, the stability of the average molecular weight is increased, the yellowing rate is reduced, and as a result, the mechanical performance is improved and the appearance is improved.

The thermoplastic polyesters obtained by the process according to the invention are used with advantageous results in all of the usual uses and techniques typical for polyesters. These are extruded and applied to various conversion techniques (eg, blow molding, injection molding, spinning, thermoforming, etc.).

In particular, the PET obtained according to the present invention is used for the production of various products (for example, containers, bottles, sheets, fiber reinforced sheets, molded products, fibers, etc.).

[0074] In order that the invention may be better understood and put into practice, the following examples are provided to illustrate, but not limit, the invention.

The materials used in the examples are commercially available, unless otherwise indicated.

[0076]

Example 1 i) Preparation of samarium tris (o-formylphenolate) About 500 ml of an aqueous solution containing 8.5 g (0.07 mol) of o-formylphenolate, and 3 g (11.7 mmol) of samarium trichloride in 500 ml of water. Added to the containing solution. The pH of the mixture was adjusted to 6-7 by adding concentrated aqueous KOH and the system was kept under stirring for 8 hours. The precipitate thus formed was collected by filtration, washed with water and dried at 60 ° C. under reduced pressure. The product obtained (obtained in quantitative yield for samarium) consists of samarium tris (o-formylphenolate).

Ii) Preparation of polyethylene terephthalate In a cylindrical reactor (1.8 liter) equipped with a stirrer equipped with a blade and a motor capable of measuring the viscosity of the molten mass, 0.506 g of samarium tris (o-formylphenolate) (9.
9 × 10 ^-4 mol) in the presence of dimethyl terephthalate (DMT)
305 g (1.572 mol) and 221 g (3.56
5 mol). The system is heated to 195 ° C. under atmospheric pressure and brought to this temperature while continuously distilling off the methanol formed.
Maintained for minutes.

The pressure was then reduced to 0.3 bar in 20 minutes and the reaction temperature was raised to 268-270 ° C. and maintained under these conditions for 2.5 hours. The resulting polyester was removed from the reactor, rapidly cooled in water, and dried in an oven at 100 ° C. and 0.3 millibar for 10 hours.

The intrinsic viscosity of the polyester thus obtained (measured in a mixture of tetrachloroethane / phenol (60/40% by weight) at a temperature of 0.3 to 1 g / dl at 25 ° C.) is 0.823 dl / g. This is the number average molecular weight 24,1
Corresponds to 00. The thermal stability of the obtained PET was evaluated by a deterioration test in a sealed ampule. For this purpose, polymer ampoules are placed in glass ampules under a nitrogen atmosphere.
0.3 g was filled, sealed and placed in a thermoblock heated to 270 ° C. for 1 hour. After this treatment, the polyester has an intrinsic viscosity of 0.622 dl / g, which corresponds to a number average molecular weight of 18,300.

[0080]

Example 2 (Comparative Example) 0.337 g (9.9 × 10 ⁻⁴ mol) of titanium tetrabutyrate was placed in a cylindrical reactor (1.8 liter) equipped with a stirrer equipped with a blade and a motor capable of measuring the viscosity of a molten mass. 305 g (1.572 mol) of DMT and 221 g (3.565 mol) of ethylene glycol were charged in the presence of.

The system was heated to 195 ° C. under atmospheric pressure and maintained at this temperature for 90 minutes while continuously distilling off the methanol formed. The pressure was then reduced to 0.3 mPa in 20 minutes and the reaction temperature was raised to 268-270 ° C and maintained under these conditions for 2.5 hours. The obtained polyester is cooled by immersing it in water, and is heated to 100 ° C in an oven.
For 10 hours.

The intrinsic viscosity of the polyester thus obtained (in a mixture of tetrachloroethane / phenol (60/40% by weight) in the range of 0.3 to 1 g / 100 ml at 25 ° C.)
Is 0.898 dl / g, which is a number average molecular weight of 2
Equivalent to 6,800. Then, 0.3 g of this polyester was treated in the same manner as in Example 1 to evaluate thermal deterioration. At the end of the test, the intrinsic viscosity of the polyester has dropped to 0.302 dl / g, which corresponds to a molecular weight of 9,100. PET having such a molecular weight is a very fragile substance that is not suitable for industrial purposes.

[0083]

Example 3 i) Europium acetylacetonate dipyridyl [Eu
(AcAc) ₃ (2,2′-dipy)] An aqueous solution containing 7 g (0.07 mol) of acetylacetone
00 ml, 3 g of europium trichloride in 500 ml of water
(11.6 mmol) was added to the solution. Adjust the pH of the mixture to 6-7 by adding concentrated aqueous KOH,
The system was kept under stirring for 8 hours. The precipitate thus formed was collected by filtration, washed with water and dried under reduced pressure at 60 ° C. for 14 hours. The solid (comprising europium acetylacetonate) was then dissolved in ethanol and a solution containing 3.7 g of 2,2'-dipyridyl in ethanol was added thereto. The mixture was kept under stirring for about 1 hour. The resulting precipitate was collected by filtration, washed with ethanol, and dried in an oven. This product is Eu (AcAc) ₃ (2,2′-dip
y) and was produced in substantially quantitative yield relative to the initial europium.

Ii) Preparation of polyethylene terephthalate Eu (AcA) was placed in a cylindrical reactor (1.8 liter) equipped with a stirrer equipped with a blade and a motor capable of measuring the viscosity of the molten mass.
c) In the presence of 0.601 g (9.9 × 10 ^-4 mol) of ₃ (2,2′-dipy),
DMT 305 g (1.572 mol) and ethylene glycol 221 g
(3.565 mol). The system was heated to 195 ° C. under atmospheric pressure and maintained at this temperature for 60 minutes while continuously distilling off the methanol formed. The pressure was then reduced to 0.3 bar in 20 minutes and the reaction temperature was increased to 268-270 ° C. and maintained under these conditions for 2.5 hours.

The resulting polyester was evaluated as described in Examples 1 and 2. The product has an intrinsic viscosity of 0.743
It had a dl / g (corresponding to an average molecular weight of 21,300). After a thermal aging test performed as described in Example 1, the intrinsic viscosity of the polyester was 0.583 dl / g (molecular weight 16,600).

[0086]

Example 4 (Comparative Example) 0.268 g of Sb ₂ O ₃ +0.247 g of Ca (OOCCH ₃ ) _{2 was} placed in a cylindrical reactor (1.8 liter) equipped with a stirrer equipped with a blade and a motor capable of measuring the viscosity of a molten mass. 9.9 × 10
The presence of ⁴ mol), was charged with DMT 305 g (1.572 mol) and ethylene glycol 221 g (3.565 mol). System at atmospheric pressure 1
Heated to 95 ° C. and maintained at this temperature for 90 minutes while continuously distilling off the methanol formed. The pressure was then reduced to 0.3 mPa in 20 minutes and the reaction temperature was raised to 268-270 ° C and maintained under these conditions for 2.5 hours.

The polyester was removed from the reactor and evaluated as described in the Examples above, which revealed that the polyester had an intrinsic viscosity of 0.854 dl / g (average molecular weight 25,200).

The heat deterioration was evaluated as described in Example 1 using 0.3 g of this polyester. After the test,
The intrinsic viscosity of the polyester is 0.250 dl / g (molecular weight 7,300
).

[0089]

EXAMPLE 5 cylindrical reactor having a motor capable of measuring the viscosity of bladed stirrer and melted lumps in (1.8 _{l), Sm (OOCCH 3) 3} · 6H 2 O 0.431g (9.9 × 10 -4 305 g (1.572 mol) of DMT and ethylene glycol in the presence of
221 g (3.565 mol) were charged. The system was heated to 195 ° C. under atmospheric pressure and maintained at this temperature for 60 minutes while continuously distilling off the methanol formed. The pressure is then reduced to 0.3 mPa in 20 minutes, the reaction temperature is increased to 268-270 ° C,
These conditions were maintained for 2.5 hours.

The polyester was removed from the reactor and evaluated as described in the above examples and found to have an intrinsic viscosity of 0.655 dl / g (average molecular weight 18,200).

Using 0.3 g of this polyester, thermal degradation was evaluated as described in Example 1. After the test,
The intrinsic viscosity of the polyester is 0.487 dl / g (molecular weight 13,500
).

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Vittorio Tartagli Via Giorgione 16 in Treviso, Italy 16 (72) Inventor Bradymir Inatov Via Via Realdi 49 in Mestre, Italy 49 (72) Inventor Birna Bonora Piazza Bagners de Bigorre, Granarolo de Remilia, Italy 3 (72) Inventor Maurigio Fiorini Via Panza Nesa 3 / D, Bazzano, Italy (56) References US Patent Application Publication 3706711 (US, A) ( 58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (14)

(57) [Claims] 1. A process for producing a thermoplastic aromatic polyester having a high degree of resistance to degradation in the molten state,
a) the aromatic dicarboxylic acid or an esterified derivative of this aromatic dicarboxylic acid with a volatile alcohol and an excess of the diol, while simultaneously removing the water or the volatile alcohol formed during the reaction, Reacting until a mixture of dicarboxylic acid diglycol esters or oligomers thereof is obtained; b) converting the mixture of dicarboxylic acid diglycol esters or oligomers obtained in step a) above to excess glycol released during polycondensation , While simultaneously removing polyisocyanate, a polycondensation step until a thermoplastic aromatic polyester is obtained. In step b) or both steps a) and b), a salt or salt complex of europium soluble in the reaction mixture is contained. A process for producing a thermoplastic aromatic polyester, comprising using as a catalyst. 2. A catalyst has the general formula (III) in MX _p L _q or general formula (IV) MY _p L _q (wherein, M is europium; X is a monovalent inorganic counter ions; each L independently represents a neutral ligand; each Y
Independently represents a monodentate organic anion; p represents the oxidation state of europium and is 2 or 3 under the condition that (p + q) is at most 8, and is a salt or a salt complex represented by the formula: A method for producing the thermoplastic aromatic polyester according to the above. 3. The catalyst according to claim 1, wherein the catalyst is of the general formula (V) B _i ML _j (where M is europium; each L independently represents a neutral ligand; B is a bidentate anionic ligand I indicates the oxidation state of europium, and (2i + j) is 4 to 8
2. The process for producing a thermoplastic aromatic polyester according to claim 1, wherein the complex is a complex represented by the following formula: 4. The process for producing a thermoplastic aromatic polyester according to claim 2, wherein the oxidation state p or i is 3. 5. The catalyst according to claim 1, wherein the catalyst is Eu (acetylacetonate).
_3. The process for producing a thermoplastic aromatic polyester according to claim 1, wherein the thermoplastic aromatic polyester is ₃ (2,2'-dipyridyl). 6. Step a) is carried out at a temperature of from 150 to 220 ° C., while gradually distilling off the water or alcohol formed during the reaction.
A method for producing the thermoplastic aromatic polyester according to any one of claims 1 to 5. 7. Step b) is carried out at a temperature of 190 to 300 ° C. and a pressure of 10 to
The method for producing a thermoplastic aromatic polyester according to any one of claims 1 to 6, which is performed at 1,000 Pascals. 8. The catalyst according to claim 1, wherein the catalyst is used in an amount of from 0.01 to 0.01% based on the aromatic dicarboxylic acid.
The process for producing a thermoplastic aromatic polyester according to any one of claims 1 to 7, used in an amount of 2% by weight. 9. The process for producing a thermoplastic aromatic polyester according to claim 8, wherein the amount of the catalyst is 0.05 to 0.5% by weight. 10. The method of claim 1, wherein the aromatic dicarboxylic acid is terephthalic acid and the glycol is ethylene glycol.
10. The method for producing a thermoplastic aromatic polyester according to any one of claims 9 to 9. 11. The process for producing a thermoplastic aromatic polyester according to claim 1, wherein dimethyl terephthalate is reacted with ethylene glycol in step a). 12. The thermoplastic aromatic polyester obtained at the end of step b) has an intrinsic viscosity (40/60 (w / w)
(Measured in phenol / tetrachloroethane solution) 0.6
2. The process for producing a thermoplastic aromatic polyester according to claim 1, wherein the thermoplastic aromatic polyester is polyethylene terephthalate having a weight of 0.9 dl / g. 13. A compound of the formula (VI)-(-O-D-OCO-A-CO-)-(wherein D and A obtained by the process according to any one of claims 1 to 12). Is a divalent organic group derived from a diol and an organic residue derived from an aromatic dicarboxylic acid, each of which has a high degree of resistance to deterioration in the molten state. A thermoplastic aromatic polyester having the formula: 14. A compound of the general formula (III) MX _p L _q , the general formula (IV) MY _p L _q or the general formula (V) _Bi ML _j (where M is europium; X is a monovalent inorganic compound) Each L independently represents a neutral ligand; each Y
Independently represents a monodentate organic anion; B is a bidentate anionic ligand; p and i indicate the oxidation state of europium, and (p + q) is a maximum of 8, or (2i +
j) is 2 or 3 under the condition that j) is an integer of 4 to 8), and a salt and / or salt complex represented by the formula (1):